Masticatory muscle activities of children (60 panelists; 4 to 6 years old) were compared with those of female young adults (54 panelists; 19 to 23 years old) on chewing some food samples with different texture. The texture of food samples was measured by a tensipresser. The food samples investigated were peanut, cooked polished rice, kamaboko (steamed fish paste), cooked unpolished rice, boiled edible burdock, pork chop, octopus boiled and seasoned, takuan (pickled Japanese radish) and surume (dried squid). The chewing frequency and the sum of the proportion of amplitudes for temporal and masseter muscles were calculated from recorded electromyograms. The results obtained were as follows. (1) The chewing frequency was significantly increased in the children compared with in the adults, except for a food sample with low hardness and chewiness. (2) For food samples with higher chewiness, both children and adults showed wide distribution of the sum of the proportion of amplitudes. (3) The sum of the proportion of amplitudes in the children was not significantly different from those in the adults for food samples with higher chewiness.